Electrical contact device



July 6, 1 937.

ELECTRICAL CONTACT DEVICE Fild May 5, 1934 aarlasflfibekler I wm w c. H. KOEHLER 86,424 7 Patented July 6, 1937 ELECTRICAL CONTACT nrrvrcn Charles H. Koehlen'Forest Park- Ill.

Application May 5, 1934, Serial No. 724,118

13 Claims.

This invention relates to electrical contact devices, and is more particularly directed to a plug and receptacle connectenwhich may be used for connecting and disconnecting an electrical cir- 5.cuit.' I

In connecting devices of the type in which a multi-contact receptacle is mounted in fixed position, such as on an instrument board, panel, or the like, and comprises a plurality of plug-receiving or socket members disposed in insulated spaced relationship thereon, the problem of providing a unit having self-adjusting and aligning characteristics, whereby a corresponding plurality of spaced contact plugs mounted in fixed position upon a base or carrier member may be engaged simultaneously. in the receptacle sockets without the-necessity of extremely accurate in dividual alignment "therebetween, presents considerable diiiiculty. 4 e

For example, in the use of a disconnecting device for an oil circuit breaker or the like, wherein .REISSU ED to enclose fully the entire contact device.

a plurality of contacts must be engaged anddis- I removal of the breaker 'from the compartment.-

Further, this control wiring ordinarily includes 35 the trip coil circuit forthe breaker, and a high grade, eiiicient contact device is thus necessary. Also, because of-its self-aligning characteristics, the present invention is capable of being em ployed in connection with the terminals of the 40 terminals of thesebreakers must-.be self-adjusting and capable of maintaining equalized contact pressure upon the male contact plugs with which the breaker terminals are engaged when the breaker is moved into operative position. a It is to be understood, however, that the invention is not to be limited to these specific uses, since the broad features thereof 'are applicable in various other fields.

The present invention, in its preferred embodiment, comprises a pair of contact shoes having a ball and socket engagement with a terminal stud,

circuit breakers themselves, sincethe sockets or andbeing enclosed within a floating housing.

The contact shoes are urged toward each other An important object attainedby the present invention is the maintenance of equal pressure between both shoes and the contact tips of the plug and terminal, these contact tips and the inner contact surfaces of the shoes being optionally silver-plated to provide a low resistance and positive current-conducting path. through the contact device. This equalization of pressure is obtained by the provision of the full-floating housing enclosing the contact shoes and biasing the outer ends of the springs, which hear, at their inner ends, against the contact shoes. Since the housing is capable of floating movement, both the contact shoes and housing are movable about the ball contact tip of the terminal stud, and consequently the contactshoes are self-aligning with respect to a male contact plug, due to this universai joint connection.

device, whereby the life of the springs is measur- 0 ably increased.

Other objects and advantages of the present invention, such as the compactness and simplicityof design of the contact device, and its manner of assembly in a multi-point disconnecting unit, will appear more fully from the following detailed description which, taken in conjunction with the accompanying drawing, will disclose to those skilled inthe art the particular construction and operation of a preferred form of my inven- 40 tion. I

In the drawing:

Figure 1 is an end elevational view of a disconnect unit employing. the present invention;

Figure 2 is a side elevational view of the unit shown in Figural, with a portion thereof broken away to show in detail the construction of the contact device;-

Figure 3 is an enlarged vertical sectional view of the contact device shown in Figure 2;

Figure 4 is a sectional view of the contact device, taken substantially on the line 4-4 of Figure 3; and

Figure 5 is an end view of'the contact device and housing, taken substantially on the line 55 of Figure 3.

Referring now in detail to Figures 1 and 12, I have shown a receptacle unit, indicated generally by the reference numeral l9, and having a substantially box-like construction terminating in an open facing portion, to which is secured an insulating panel'member l2. The panel member l2 closes the receptacle housing l9 and, in addition, is provided with a plurality of stud or pillar members indicated at I3, secured to the panel l2 and extending rearwardly therefrom to support a second insulating panel Ml thereon. I preferably provide six of these pillars l3, in order to provide adequate support for the secondary panel it, the pillars being provided with spacing bushings for maintaining the secondary panel Hi in spaced relation to the closure panel l2.

Mounted upon the secondary panel M are a plurality of terminal studs, indicated at l 5, which extend through the-panel and have ball contact tip portions, indicated at it, and rearwardly extending collar portions i'l abutting against one faceof the panel it. A plurality of nuts l9 are threaded onto each of the studs l5 for securing the same in position upon the panel M, there being a washer l9 interposed therebetween. The

. nuts I8, with the washer l9, form securing means for the terminal ends of a plurality of conductors extending into the receptacle housing l through the opening 29 at the base thereof. These conductors are selectively connected to the various ternzinal studs i within the receptacle housing 0.

As shown, I have indicated eleven of such con-, tact or terminal'studs; although it is obvious that any desired number of studs may be employed and arranged symmetrically within the housing. Mounted over the ball contact tip it of the plug I5 is a pair of contact shoes 22'and 23, which are preferably formed of forged copper and. which are suitably recessed to engage about the contact tip it and to have universal ball and socket connection therewith. The contact shoes 22 and 23 are provided with a raised centrally located boss portion 24, which is adapted toserve as a seat forv one end of a spring member 25, the opposite ends of the spring members 25 being biased against the inner periphery" of a housing 26 which has floating engagement therewith, the housing 26 being substantially rectangular in shape, as shown clearly in ,Figure 5, and being of a length so that it extends from the shoulder portion ll of the stud-l5 to a point slightly forwardly of the forward ends of the shoes 22 and 23, thereby completely enclosing the contact device. The housing 26 may be formed of insulating material, as shown, if desired.

The outer ends of the shoes 22 and 23 are contacting surfaces of the shoe members 22 and 23 are silver-plated, in order to provide alow resistance contact between these members, and

, current is transmitted through a path including the contact shoes and the ball contact tips l6 and 28, thereby preventing any electrical current from passing through the springs 25, which measurably increases the life of these springs and allows them to retain their resiliency for a greater period of time, due to the fact that they are not heated by any electric current passing therethrough.

The male contact plugs 29 are carried by an insulating base member 30, which member forms a closure for one face of the plug housing 3i;

This housing is preferably formed of metal, and

'is provided with laterally extending flange porflanged portions 35 of the receptacle housing 90.

A pair of countersunk screws 36 are threaded into the flanges 35 to secure the base member l2 in abutting engagement with the flanges. A second pair of countersunk screws 36 are threaded into flanges 32 and 33 opposite the stud openings extending therethrough for securing base member 30 to the flanges 32 and 33. The housing 3| may thus be secured in position over and telescoping with the housing Ill, and simultaheously the contact plugs 29 carried by member 39 are engaged within the contact shoes 22 and 23. The contact studs 29 are adapted to carry a plurality of'nuts 31 threaded onto the projecting ends thereof,

.these nuts serving to secure conductors to" the contact plugs 29, the conductors entering into the housing 3| through an opening 38 formed in the base thereof.

In the particular type of disconnect unit shown,

' there are provided eleven contact devices and a corresponding "number of contact plugs 29, the

plugs. 29 being spaced with respect to the base tip I6 of the terminal plug L5, and due to the fact that the housing 26 has full floating movement with respect to the terminal plug, any slight misalignment between the studs I 5 and 29 can be accommodated by a corresponding movement of the shoes about the ball and socket joints at the ball contact tips I 6. Further, equal pressure will be maintained, due to the fact that the springs are biased between the shoes and the floating housing, so that upon movement of the shoes the housing moves therewith, and the'spring pressure is maintained equally upon both of the shoes.

It is obvious'that the invention is equally applicable for other uses, such asfor use in connec tion with circuit breakers, where the contact plugs 29 may comprise'the fixed terminals in the switch gear structure, with the contact devices including the shoes 22 and 23, having insulating housing 26 thereabout, comprising the socket terminals carried by the breaker, which: are engaged about the plugs when the breaker ismoved intoposition.

Further, it isapparent that in place of two contact shoes 22 and 23, any desired number of contact shoes may be provided, the housing 26 in such instance being formed to take the shape of the outer periphery'of the contact device, and a plurality of spring means corresponding 'to'the number of shoes employed beingbiased between the shoes and the housing.

It is thus apparent that I have provided an electrical contact device which provides for selfthe two contact members.

Having described my invention in accordance with thepatent statutes, what I claim as new and desire to secure by Letters Patent is;

1. An electrical contact device comprising a terminal stud having a ball contact tip, a plurality of contact shoes recessed to have ball and socket engagement about said tip and defining a cylindrical opening extending outwardly of said tip, an enclosing housing supported about said shoes, spring means biased against said housing and saidshoes, and a male contact plug engageable within the opening formed by said shoes, said spring means equalizing the pressure between each-of said-shoes and said contact tip and contact-plug.

2. An electrical contact device comprising a plurality of contact shoes having universal movement about a fixed ball contact member and defining a plug receiving opening, a plug member having a contact portion engageable within said opening, ahousing of the same inner peripheral shape as the outer defining periphery of said contact shoes and enclosing the same, and spring means biased against said shoes and said housing supporting said housing for conjoint movement with said shoes and normally urging said shoes inwardly for equalim'ng the contact pressure of said shoes. r

3. An electrical contact device comprising a plurality of cooperating contact shoes interiorly,

recessed at one end thereof to define a socket opening, a ball contact member engaged within said socket'opening and providing for universal movement of said contact device thereabout, an enclosing housing about said shoes, spring means bearing against said shoes'and said housing to support said housing in position for conjoint movement of said housing upon movement of said defining a cylindrical opening for receiving a contact plug, a housing extending about said shoes, and spring means biased between the outer surface of each of said shoes and the inner surface of'said housing normally urging said-shoes inwardly, saidhousing'having free floating support upon saidshoes.

position on a supporting member and engageable within the corresponding contact device, said spring means equalizing the pressure contact between said shoes and said plug.

6. In combination, an insulating supporting member, a plurality of terminal studs extending therethrough and having projecting ball contact tipportions, contact devices engaging about each of said contact tip portions, each of said contact devices comprising aplurality of cooperating con-, tact shoes having ball and socket engagement with said tip portions, an open-ended housing disposed about said contact shoes, and spring means biased between each of said plurality of shoes and said housing for supporting said housing thereon; and a plurality of contact plugs mounted in fixed position on a supporting member and engageable within the corresponding contact'device, said ball and socket engagement providing for in 'vidual aligning of said contact devices with sai plugs.

7. In combination, a contact plug havinga ball contact portion, a contacting 'device .adapted to receive said plug comprising a terminal stud having a ball contact portion, contact means engaged thereabout-for universal movement with respect thereto and defining an expansible and contractible opening for receiving the contact portion of said plug, enclosing housing means dis posed about said contact means, and spring means biased between said housing means and said contact means.

8. In an electric contact device, a plurality of cooperating contact shoes defining a plug-receiving opening, a contact tip projecting from a fixed support and having a rounded contact surfaceengaged by said shoes and supporting said shoes for universal movement thereabout, an open-ended enclosing housing for said shoes and fitting thereabout, spring means biased between each of said shoes and the inner surface of said housing, and a contact plug adapted to be inserted into said plug-receiving opening, said shoes and housing being shiftable about said tip to accommodate axial misalignment between said plug and said tip.

. 5. In combination, an insulating supporting member, a plurality of terminal studs extending therethrough and having projecting ball contact 'tip'portions; contact devices engaging about each .01 said contact tip portions, each of said contact devices comprising a plurality of cooperating contact shoes having ball and socket engagement with said tip portions, an open-ended housing disposed about said contact shoes, spring means biased between each oi.- said plurality of shoes and said housing for supporting said housing thereon,

9. In combination, a supporting member, a contact tip extending therethrough and having a spherical contact portion, a'plurality of contactshoes defining aplug-receiving opening and,

having concave spherical contact surfaces for cooperating with said spherical contact portion to 'permit limited universal movement about the contact portion of said tip, a second supporting member mounted in spaced parallel alignment with said first supporting member and having an insulated opening substantially aligned with said plug-receiving opening, a contact plug adapted to be inserted through said insulating opening andengageablewithin saidplug-receiving opening, and means for resiliently urging said shoes into contacting engagement with said con- ,tact tip and said contact plug.

ing outwardly from a fixed support, a plurality of shoes having means formed in one end thereof for mounting said shoes for universal movement about said tip, said shoes defining at their opposite ends a socket for receiving a male contact plug, supporting means resiliently carried by said shoes and movable therewith about said tip, and spring means biased between said shoes and said supporting means for urging said shoes toward each other, said supporting means and shoes being automatically moved about said tip upon insertion of a male contact plug thereinto for accommodating misalignment between said tip and plug.

12. An electrical contact device for connecting a male contact plug to a fixedcontact terminal comprising a plurality of contact shoes defining a cylindrical plug-receiving socket at one end thereof, means at the opposite end of said shoes mounting said shoes for universal movement about said fixed terminal, a sleeve enclosing said shoes and terminating adjacent the ends thereof, and spring means biased between the interior surfaces of said sleeve and the exterior surfaces of said shoes forresiliently urging said shoes into contacting engagement, said sleeve having floating support upon said shoes.

13. In combination, a first insulating supporting member, a contact terminal mounted thereon and projecting from one surface thereof, a second insulating supporting member extending parallel to and spaced from said first supporting member, said second member having an enlarged opening substantially in alignment with said terminal and adapted to receive a projecting male contact plug, and means for establishing connection between said plug and said terminal comprising a pair of contact shoes, a sleeve of less axial length than the space between said supporting members enclosing said shoes, means biased against the interior lateral surface of said sleeve for urging said shoes into contacting engagement between said plug and terminal, and means at one end of said shoes providing for universal movement of said shoes and sleeve about said terminal. 

